It is well known that in electrical generators and electrical motors there is a cylindrical rotor which rotates about a shaft inside a cylindrical stator which is fixed to the frame of the machine. The rotor rotates at high speed and its surface must be very close to the surface of the stator in order to have an efficient machine. Any looseness in the bearings on which the rotor rotates, any weakness in the assembly of rotor components that might permit a part to break away from the rotor while rotating, or the presence of any foreign body between the rotor and stator may cause extensive and expensive damage to occur to the rotor and/or stator before that damage can be detected. Accordingly, it is important to have means for detecting impending damage before it occurs to any series extent.
It is an object of this invention to provide a means for detecting physical contact between the rotor and stator. It is another object of this invention to provide an improved means for detecting worn shaft bearings on a rotor. It is another object of this invention to detect any foregin body that is electrically conductive between the rotor and stator. Still other objects will be apparent from the more detailed description of this invention which follows.